In general, portable electronic devices are increasingly portable and support a variety of functions. For example, the electronic devices can perform various functions such as alarm, short messaging service, Multimedia Messaging Service (MMS), e-mail, game, short-range communication remote control, image capturing using an embedded digital camera, multimedia function for providing audio and video contents, and scheduling.
The more a portable electronic device diversifies its function, the more competitive it will be in the marketplace. For example, users generally prefer the slimmer portable electronic device with a simpler user interface capable of executing the same set of functions. Accordingly, portable electronic device manufacturers compete to develop slimmer and simpler devices relative to other products with the same or better functions.
Hence, an interface for executing and controlling the various functions of a portable electronic device is in high demand, although there is a limit to the configuration of the physical user interface for facilitating various input functions in a slim electronic device.